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Musa acuminata ssp. burmannica


Musa acuminata ssp. burmannica

Image

Order

Zingiberales

Family

Musaceae

Genus

Musa

Section

Musa

Species

Musa acuminata

Subspecies
burmannica

Musa acuminata ssp. burmannica[1] is the  name of a subspecies of Musa acuminata, the wild species involved in the domestication of the vast majority of cultivated bananas. According to CIRAD scientists, it is one of four main subspecies of Musa acuminata that have contributed to the genetics of edible bananas[2][3].

Musa acuminata ssp. burmannica is an accepted name in Hakkinen and Vare's chekclist of Musa names[4], but is considered a synonym of Musa kattuvazhana by R. Govaerts[5].

One of the best known genebank accessions of Musa acuminata ssp. burmannica is Calcutta 4, whose resistance to various diseases has made it popular with breeders.

Taxonomy

The original recognition of this form of Musa acuminata was made in 1948 by E. E. Cheesman, who although did not formally publish it as a taxon, described it and identified it as the 'Tavoy' form of Musa acuminata, because the specimen came from Tavoy (now Dawei in Myanmar)[6]. In 1956, Norman Simmonds formally upgraded its classification to a distinct subspecies[1].

In 1960, De Langhe split Musa acuminata Colla ssp. burmannica Simmonds into two subspecies: Musa acuminata Colla ssp. burmannica Simmonds emend. De Langhe and Musa acuminata Colla ssp. burmannicoides De Langhe subsp. nov.[7].

It was between the original recognition and Simmond’s publication that in 1952 Musa kattuvazhana was published in a monograph on the bananas of the Madras province of India by K. Cherian Jacob[8]. The name  fell into obscurity and apparently evaded the notice of Simmonds.  If he was aware, it did not draw any suspicions of being allied with the Musa acuminata complex he was trying to sort out. Not a single mention of the species Musa acuminata is made in the monograph. Moreover, a profile of the introduced Musa textilis clearly depicts forms of Musa balbisiana, revealing a less than expert knowledge of wild Musa.

In 2016, the once lost and mostly unknown name M. kattuvazhana was revived after extensive field studies, and subsequently identified as being synonymous with M. acuminata subsp. burmannica, as well as M. banksii var. singampatti on literature based morphological grounds[9]. Perhaps too eagerly, and with arguably dubious justification, subsp. burmannica was reduced under M. kattuvazhana. It would seem that perhaps the theoretical combination M. acuminata subsp. kattuvazhana may be more appropriate taxonomically, however even such a compromise is unlikely to be widely accepted as ‘Calcutta 4’ and ‘Long Tavoy’ have both been long ingrained into the Musa research community as belonging to subsp. burmannica. To change course would require monumental revision to the literature and undoubtedly impose much undue complexity in a field which is desperately seeking simplicity and clarity.

Distribution

Myanmar: Tavoy District

India: Madras Province, Western Ghats

Main morphological characteristics

The material Cheesman described[6] came from Myanmar (formerly Burma) and comprised two collections: I.R. 124 (Clone Calcutta 4)  and I.R. 187 (Clones Tavoy and Long Tavoy). The Burmese name was given in both cases as Taw-byaw, and the two collections differ only slightly in quantitative characters such as size of bunch and length of fruit, important to the banana breeder but not to the systematist. The three clones may therefore be referred to collectively as " the Tavoy form " with the following characters.

Upper parts of leaf-sheaths bright green, with heavy reddish brown blotching, not at all waxy; leaf blades not glaucous beneath, midribs pale green or yellowish; petioles relatively stout, with well developed erect margins, very early becoming scarious where appressed to pseudostem. Male bud in advanced blooming acute, the bracts usually distinctly imbricate at the tip ; bracts dark violet-purple and glaucous outside, light red and shining within. Male flowers whitish, the bright yellow teeth of the compound tepal up to 7 mm. long. Fruit bunch pendent and compact, its peduncle densely pubescent ; fruit 8-12 cm. long, pedicel very short and not very distinct, acumen about 0-5 cm. long, withered style tending to persist.

According to Simmonds, the subspecies is distinguished by its yellowish and waxless foliage, light brown markings on the pseudostem and by its compact pendulous bunch and strongly imbricate purple bracts[1].

Synonyms

Musa acuminata ssp. burmannicoides[7] is considered a synonym of Musa acuminata ssp. burmannica[10].

The nuclear, choloplastic and mitochondrial genomes of genebank accessions of Musa acuminata ssp. burmannicoides, ssp. burmannica and ssp. siamea accessions are similar[11]. Musa acuminata subsp. siamea, an accpeted subspecies, may also be a synonym[2].

References

1. Simmonds, N.W. 1956. Botanical results of the banana collecting expedition, 1954-5. Kew Bulletin 11(3):463-489.
2. Perrier, X., Bakry, F., Carreel, F., et al. 2009. Combining biological approaches to shed light on the evolution of edible bananas. Ethnobotany Research and Applications 7:199-216.
3. Perrier, X., De Langhe, E., Donohue, et al. 2011. Multidisciplinary perspectives on banana (Musa spp.) domestication. PNAS 108(28):11311-11318.
4. Häkkinen, M. and Väre, H. 2008. Typification and check-list of Musa L. names (Musaceae) with nomenclatural notes. Adansonia 30(1):63-112.
5. Musa acuminata subsp. burmannica N.W.Simmonds, not accepted by R. Govaerts, compiler of World Checklist of Musaceae. Retrieved 19 February 2018.
6. Cheesman, E.E. 1948. Classification of the bananas III. Critical notes on species. Kew Bulletin 3(1):11-28.
7. De Langhe, E. and Devreux, M. 1960. Une sous-espèce nouvelle de Musa acuminata Colla. Bull. Jard. Bot. Etat Brux. 300: 375–388.
8. K.C. Jacob. 1952. Musa kattuvazhana, pp. 129-130 in Madras bananas, a monograph. Madras, India.

Also on this website

Musapedia pages on subspecies of Musa acuminata